GB863454A - Wet material reduction mill - Google Patents

Abstract

863,454. Wet grinding mills. WESTON, D. Jan. 4, 1960 [Jan. 28, 1959], No. 261/60. Class 59 A wet combined crushing and grinding mill comprises a rotatable drum having end walls 11, 12 and a peripheral wall 13, the ratio of the interior diameter of the drum to the interior length thereof being at least 2:1, a plurality of spaced crusher bars 20 to engage the largest particles of feed, means 32 for feeding material and means 33 for feeding water and oversize return to the mill, grate discharge means 34 and annular keying liners 23, 24 mounted on the walls 11, 12, the liners collectively penetrating into the mill interior from about 20% to about 80% of the effective mill length and defining a keying zone which is about 30% to about 75% of the effetcive mill volume. The grate discharge 34 is formed of a conical inner part 35 and a grate 36 which comprises a solid inner portion surrounded by a grate structure 38, the whole being supported within the part 35 by bracer elements 39 which also function as lifters assisting discharge. The discharged material may be deposited into a classifier box and fed into a helical classifier; alternatively, the discharged material may pass directly to a screen. The discharge may be assisted by means of an air stream, air or steam jets or various mechanical arrangements. Alternative forms of keying liner are described and shown. In a modification, Fig. 5, the mill is provided with a false inner wall 50 having grate openings 51, lifters 52 disposed between the wall 50 and the wall 11 for carrying the discharged material radially inwards where it is deflected by the conical surface 53 of the central portion of the wall 50 and permitted to flow over the trunnion liner member 54 for discharge. In another modification, Fig. 7, the parts 50 to 52 are the same as in Fig. 5 but in this case the inner extremity of the space between the wall 50 and wall 11 is sealed off by the flange 53 whereas the peripheral wall 13 is provided with grates 54 permitting the discharged material to pass directly outwardly for collection in a trough 55. Specifications 632,532, 696,137 and U.S.A. Specification 2,094,842 are referred.